Discussion
We encountered an OGIB patient who eventually experienced small
intestinal stricture due to MD. The clinical course of this patient
suggests two important clinical issues. First, although the frequency is
low, OGIB patients may have small intestinal strictures due to
inflammation from MD. Second, the diagnosis of bleeding due to MD is
still sometimes difficult to determine, even when using several
diagnostic modalities.
In the present case, intestinal stricture due to MD was diagnosed by
BAE after the second occurrence of hematochezia. Although capsule
retention was avoided with this patient, transient capsule retention
inside the MD has been reported in other cases [10]. A possible
explanation of the clinical course of the present case was that the
bleeding from the ulcer in the ileum occurred; thereafter, stricture
developed as a result of scar formation after ulcer healing. The ulcer
formed due to exposure to acid secretion from the heterotopic gastric
mucosa of MD. Because we performed CE after the second occurrence of
hematochezia, there was a possibility that capsule retention might occur
since the stricture was too severe to traverse with an enteroscope. More
commonly, capsule retention due to drug-induced stricture from
non-steroidal anti-inflammatory drugs has been reported, usually
presenting as diaphragmatic stricture [11, 12]. Rezapour M et al.
conducted a meta-analysis of retention associated with CE and reported
that capsule retention occurred in 2.1% of patients with OGIB [9].
Furthermore, 3% of patients with capsule retention in that
meta-analysis developed obstructive symptoms. Patency CE is used for
patients who have a high risk of intestinal stricture, and reports
indicate that it has reduced the risk of capsule retention by half with
IBD patients [9]. Performing patency CE for all OGIB patients is not
recommended, considering the low incidence of stricture due to MD (such
as our case), but endoscopists should keep in mind the possibility of
stricture due to MD when examining OGIB. If the possibility of MD is
already high with other modalities, patency CE may be an option before
CE.
It was difficult to diagnose MD before surgery with the present case.
Several specific diagnostic tools have been reported to help diagnose
MD, including arteriography, technetium 99m pertechnetate scan, CE, and
BAE. Among these, arteriography and technetium 99m pertechnetate scan
are regarded as the standard tools to diagnose MD. If bleeding is heavy,
arteriography can be a good option. In patients who have less bleeding,
high-resolution CT arteriography can be a good option, and its overall
sensitivity for detecting active acute GI bleeding is reported to be as
high as 85.2 % [13]. If bleeding stops spontaneously, it could be
difficult to detect the source of bleeding with high-resolution CT
arteriography. The technetium 99m pertechnetate scan failed to diagnose
the presence of MD with the present case, although the heterotopic
gastric mucosa was confirmed pathologically after surgery. The
sensitivity of the technetium 99m pertechnetate scan for adult MD has
been reported to be approximately 60% [6]. Krstic SN et al.
reported that CE had a high positive predictive value of 84.6 % for the
diagnosis of MD [4]. However, in the same study, CE identified the
source of bleeding in only 44.6% of OGIB patients. In the present case,
several diagnostic tools, including high-resolution CT arteriography,
technetium 99m pertechnetate scan, and CE, failed to diagnose MD.
Considering the insufficient sensitivity of some tests to diagnose MD,
several examinations, including BAE, should be carried out to diagnose
MD. Although BAE is an invasive procedure, it could be sometimes a
preferable option compared with other modalities, especially for the
diagnosis of MD [5, 14].
In addition to the difficulty of MD diagnosis, we should keep in mind
the possibility of intestinal stricture due to MD when seeing OGIB
patients.